1. Field of the Invention
This invention generally relates to a dynamic damper and a flywheel assembly. More specifically, the present invention relates to a dynamic damper which rotates with an input shaft of a transmission for dampening vibrations.
2. Background Information
In connection with such a dynamic damper and a flywheel assembly, the assignee has already developed prior arts disclosed in Japanese Laid-Open Patent Publication No. 6-48031 (1994) and others.
In the above prior arts, a second flywheel forming a mass portion is coupled to a drive and transmission system through a torsional damper mechanism to dampen a torsional vibration on the drive and transmission system only when a clutch disk is pressed against a first flywheel. Thereby, an operation impeding shifting of the transmission is suppressed in a disengaged state of a clutch while suppressing gear noises (neutral noises) of the transmission in a neutral state as well as vibrations and noises of the transmission during driving of a vehicle.
In the above prior art, a friction plate in a friction reducing mechanism (sub-clutch) moves in accordance with an axial distance of movement of the clutch disk, and thereby the second flywheel is coupled to the drive and transmission system.
However, the clutch disk has facings (friction members) which are worn due to friction with the first flywheel and others. When the facings are worn, the distance of axial movement of the clutch disk changes, which affects the operation of the sub-clutch. More specifically, wearing of the facings of the clutch disk may cause such disadvantages that a torque transmission capacity of the sub-clutch shifts from a predetermined value and that the sub-clutch cannot engage and disengage the second flywheel with respect to the drive and transmission system in an intended manner. As a result, an effective operation of the dynamic damper is impaired to a higher extent in accordance with wearing of the facing, and thereby a performance of dampening the vibration of the drive and transmission system is impaired.
In view of the above, there exists a need for a dynamic damper and a flywheel assembly which overcomes the problems of the above-mentioned prior art. This invention addresses these needs in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.